You need to edit the SkyrimPrefs.ini file located at C:Users[USERNAME]DocumentsMy GamesSkyrim
Find the lines iSize H= and iSize W= and add in the resolution you want after the = to give iSize H=1080 and iSize W=5760
When I run Skyrim BEFORE editing the SkyrimPrefs.ini file I have the following resolution options:
1280x720 (Letterbox)
1600x900
1920x1080
The only iSize settings I have in SkyrimPrefs.ini
iSize H=1080
iSize W=1920
I have three monitors, eyefinity at 5760x1080
I edit the SkyrimPrefs.ini to:
iSize H=1080
iSize W=5760
Run Skyrim, I now have NO resolutoin options in the dop down menu.
I still get the same error, i.e. the game dupliacted on all 3 monitors.